This project consists of two distinct parts: First is the exact determination of the composition/structure of several adjuvants and adjuvant formulations (i.e. 1-O-Octyl-B-glucoside, oil in water emulsions, QS21, MPL and Alum), and second part examines the use of polysaccharides microspheres as a vaccine delivery system. These projects have been seriously hampered by our inability to determine size and size distribution of micelles, and particles. For that reason we have undertaken to setup a Multi Angle Laser Light Scattering (MALLS) facility to measure the size and size distribution of adjuvants and particle delivery systems. We have so far setup and validated the photometer for its ability to measure weight and size distributions of macromolecules. We are in the process of adding an Asymmetric Field Flow Fractionator to the photometer to measure weight and size distribution of particles and emulsions. Preliminary work has demonstrated that we can obtain information on the solution behavior of adjuvants both through the measurement of their change in refractive index with concentration (where marked shifts in the slope of the dn/dc lines have been observed) and in a direct measurement of molecular weight with AFFF-MALLS. This capability will allow us to complement our NMR and computational modeling work in giving us a detailed understanding of the solution interactions of adjuvants and antigens.